Our invention concerns an apparatus for reciprocably moving a desired object. The apparatus in accordance with our invention finds a typical, and not exclusive, application as a vehicle window regulator, that is, a device for opening and closing a vehicle door window.
While a great variety of vehicle window regulator configurations have been suggested and used, no small percentage of them employ drive tapes of a rigid, but somewhat flexible, plastic for power transmission from a hand crank or a reversible electric motor to the pane or panel of glass or like material closing the window. We will describe one known window regulator with a such drive tape in order to make clear the problems heretofore encountered in the art.
Coiled on a tape reel rotatably mounted to the vehicle door frame, the drive tape slidably extends through a tape guide of channel section secured to the door frame. The tape guide includes a first portion extending diagonally upwardly from the tape reel and a second portion extending vertically downwardly from the upper extremity of the first portion, with the first and second portions being joined via a somewhat gently curved bight portion. The drive tape is fastened to the bottom edge of the window panel at that point of the drive tape which is located at or adjacent the top end of the vertical second portion of the tape guide when the window panel is closed. Thus, by paying off the drive tape from the tape reel, the window panel can be lowered toward an open position as the drive tape travels down the vertical second portion of the tape guide. The rewinding of the drive tape causes the window panel to slide upwardly to a closed position.
As will be readily apparent, the window can be easily closed by this prior art window regulator as the window panel is raised by rewinding the drive tape onto the tape reel. The opening of the window is not easy, however. Unwound from the tape reel, the drive tape by reason of its flexibility does not necessarily effectively transmit the force on the tape reel to the window panel. This has been all the more so because the window panel must travel up the door frame, and the drive tape must move through the tape guide, both in opposition to considerable frictional resistances. We also object to the drive of drive tapes because, being subjected to repeated tension and compression, they are questionable in durability.
We are aware of conventional window regulators that employ wire in substitution for plastic tape. However, wire represents no substantial improvement of plastic tape in respects of durability, performance and friction.